This is ringing pretty similar to me. I too live in WA and last year bought my 53 5 window in Bend Oregon (Rented a Uhaul car trailer too). My truck had a Oregon title and the VIN on the title was the Engine number not the body number on the door tag. Luckily I went back to Bend last summer and retrieved the original 216 out of the PO's storage unit. I had no trouble transferring the title, no inspection by the state patrol but I had a title and bill of sale. Did you get a bill of sale? I would get the title problem sorted out before I did anything on this truck personally, you know how these things can go south in a hurry especially after you start dumping $$ in them. Good buy and cool looking truck too.
Steve

1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration